Practical Experience in Large-Scale Development of Zijinshan Low-Grade Gold-Copper Mine

2020 ◽  
Vol 37 (4) ◽  
pp. 1339-1347 ◽  
Author(s):  
Jinghe Chen ◽  
Shuiping Zhong ◽  
Ding Tang ◽  
Chen Kuang
2021 ◽  
Vol 11 (11) ◽  
pp. 5208
Author(s):  
Jianpo Liu ◽  
Hongxu Shi ◽  
Ren Wang ◽  
Yingtao Si ◽  
Dengcheng Wei ◽  
...  

The spatial and temporal distribution of tunnel failure is very complex due to geologic heterogeneity and variability in both mining processes and tunnel arrangement in deep metal mines. In this paper, the quantitative risk assessment for deep tunnel failure was performed using a normal cloud model at the Ashele copper mine, China. This was completed by considering the evaluation indexes of geological condition, mining process, and microseismic data. A weighted distribution of evaluation indexes was determined by implementation of an entropy weight method to reveal the primary parameters controlling tunnel failure. Additionally, the damage levels of the tunnel were quantitatively assigned by computing the degree of membership that different damage levels had, based on the expectation normalization method. The methods of maximum membership principle, comprehensive evaluation value, and fuzzy entropy were considered to determine the tunnel damage levels and risk of occurrence. The application of this method at the Ashele copper mine demonstrates that it meets the requirement of risk assessment for deep tunnel failure and can provide a basis for large-scale regional tunnel failure control in deep metal mines.


2021 ◽  
pp. 1-8
Author(s):  
Pillkyu HWANG ◽  
Yae-Ahn PARK

On 23 July 2018, when the villagers gathered around the porch to wrap up the day with a good chat, one of the five auxiliary dams of the Xe-Pian Xe-Namnoy hydropower dam in Attapeu province, the southeastern state of Laos, collapsed. Four days before the collapse, reports of cracks and subsidence started to come through. It should have been enough to prompt evacuation warning issuance by the Xe-Pian Xe-Namnoy Power Co. Ltd (PNPC), a consortium of South Korean companies SK Engineering and Construction (SK E&C) and Korea Western Power Company (KOWEPO), Thailand-based RATCH Group, and Lao Holding State Enterprise (LHSE). PNPC has a Concession Agreement with the Laos government ‘to plan, design, finance, construct, own, operate and maintain’ the Xe-Pian Xe-Namnoy hydropower dam. The warning was issued, but it came too late.


2021 ◽  
pp. 751-756
Author(s):  
Sevostyanov A.V. Sevostyanov A.V. ◽  
V.A. Sevostyanov ◽  
A.P. Spiridonova

This article covers the issues raised by the objectives of the "The Program for complex development of rural territories" and its subprogram "Providing rural population with affordable and comfortable housing". The authors substantiate the concept "rural agglomeration" and make the suggestions on how to choose rural settlements and land plots suitable for large-scale development of low-density residential areas.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Ole Grøn ◽  
Lars Ole Boldreel

Archaeological wrecks exposed on the sea floor are mapped using side-scan and multibeam techniques, whereas the detection of submerged archaeological sites, such as Stone Age settlements, and wrecks, partially or wholly embedded in sea-floor sediments, requires the application of high-resolution subbottom profilers. This paper presents a strategy for cost-effective, large-scale mapping of previously undetected sediment-embedded sites and wrecks based on subbottom profiling with chirp systems. The mapping strategy described includes (a) definition of line spacing depending on the target; (b) interactive surveying, for example, immediate detailed investigation of potential archaeological anomalies on detection with a denser pattern of subbottom survey lines; (c) onboard interpretation during data acquisition; (d) recognition of nongeological anomalies. Consequently, this strategy differs from those employed in several detailed studies of known wreck sites and from the way in which geologists map the sea floor and the geological column beneath it. The strategy has been developed on the basis of extensive practical experience gained during the use of an off-the-shelf 2D chirp system and, given the present state of this technology, it appears well suited to large-scale maritime archaeological mapping.


2014 ◽  
Vol 2014 ◽  
pp. 1-11 ◽  
Author(s):  
Nicola Caterino ◽  
Mariacristina Spizzuoco ◽  
Julian M. Londoño ◽  
Antonio Occhiuzzi

This work focuses on the issues to deal with when approaching experimental testing of structures equipped with semiactive control (SA) systems. It starts from practical experience authors gained in a recent wide campaign on a large scale steel frame structure provided with a control system based on magnetorheological dampers. The latter are special devices able to achieve a wide range of physical behaviours using low-power electrical currents. Experimental activities involving the use of controllable devices require special attention in solving specific aspects that characterize each of the three phases of the SA control loop: acquisition, processing, and command. Most of them are uncommon to any other type of structural testing. This paper emphasizes the importance of the experimental assessment of SA systems and shows how many problematic issues likely to happen in real applications are also present when testing these systems experimentally. This paper highlights several problematic aspects and illustrates how they can be addressed in order to achieve a more realistic evaluation of the effectiveness of SA control solutions. Undesired and unavoidable effects like delays and control malfunction are also remarked. A discussion on the way to reduce their incidence is also offered.


2014 ◽  
Vol 2014 ◽  
pp. 1-14 ◽  
Author(s):  
Widiatmaka ◽  
Atang Sutandi ◽  
Anas Iswandi ◽  
Usman Daras ◽  
Muhammad Hikmat ◽  
...  

Commodity development requires site selection which should be established prior to large scale development. The land suitability criteria for cashew are not presently available. The relationship between the biophysical aspects, especially land and soil with commodity productivity, is also not known in depth. The objective of this study is to establish the criteria of land suitability for cashew in Indonesia, based on its production and land characteristics. Cashew plantations in 5 provinces were sampled. The data of production per tree per year were obtained from farmers, while the soil was sampled and analyzed in the laboratory. Age-adjusted cashew production was used as the yield response and plotted against land characteristics. Boundary lines resulting from the scatter of points were described; these lines produced the limits of land suitability criteria. The criteria were established using a projection of the intersection between the boundary line and yield interval. The criteria were also built in accordance with the productivity index of FAO for the internal boundary inside the S (suitable) class and by calculating the break-event point production for the boundary between S (suitable) and N (nonsuitable) order. The main result of this research is land suitability criteria for cashew.


Author(s):  
Jian Song ◽  
Chun-wei Gu

Energy shortage and environmental deterioration are two crucial issues that the developing world has to face. In order to solve these problems, conversion of low grade energy is attracting broad attention. Among all of the existing technologies, Organic Rankine Cycle (ORC) has been proven to be one of the most effective methods for the utilization of low grade heat sources. Turbine is a key component in ORC system and it plays an important role in system performance. Traditional turbine expanders, the axial flow turbine and the radial inflow turbine are typically selected in large scale ORC systems. However, in small and micro scale systems, traditional turbine expanders are not suitable due to large flow loss and high rotation speed. In this case, Tesla turbine allows a low-cost and reliable design for the organic expander that could be an attractive option for small scale ORC systems. A 1-D model of Tesla turbine is presented in this paper, which mainly focuses on the flow characteristics and the momentum transfer. This study improves the 1-D model, taking the nozzle limit expansion ratio into consideration, which is related to the installation angle of the nozzle and the specific heat ratio of the working fluid. The improved model is used to analyze Tesla turbine performance and predict turbine efficiency. Thermodynamic analysis is conducted for a small scale ORC system. The simulation results reveal that the ORC system can generate a considerable net power output. Therefore, Tesla turbine can be regarded as a potential choice to be applied in small scale ORC systems.


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